AP "Calibration Components"

Have recently come into possession of some military calibration components that I have never seen before.

The box is marked as follows:

Calibration Components
AP 30M2
LOT FA Y 30-374
16 Oct 1952

The boxes are fairly pristine but yellowed with age.There are 66 bullets in each box. I paid $50 for them but really have no idea as to what they might be worth.



I’m not sure if you’re asking what they are, or what they’re worth? Or both?

They are Frankford Arsenal, cal 30 M2 Armour Piercing from 1952.

Few of us on the Forum are comforatble with talking values, especially not seeing the item in person. But I’d say they must be worth $50 to at least one person. ;)


I don’t evaluate cartridges but I can tell you that the bullets out of the box have a value of pennies. It is the box that is collectable. One does not see “Calibration Component boxes” every day. I don’t know if it is worth what you paid generally speaking or not. Generally, the real worth of an item is whatever someone will pay for it. If an item is offered to a wide selection of people with an interest in it, for say $100.00, and no one buys it, it isn’t worth $100.00. The proof of that is obvious - no one would buy it in our make-believe scensario.

Calibration components were general selected for near perfection, for assembly into ammunition for testing of firearms for one reason or another. Another use was to provide a specification “ideal” for comparison to similar manufactured items. Unfortunately, the precision for which these components were selected “disappear” out of the box, and become just another case, primer or bullet. It is the box itself that is the collectable. Outside of the box, the contents lose their identity.

I have seen boxes of “proof loads” before but have never seen the bullets as an individual component. That is what struck me as being strange and that is why I purchased them.

The boxes are in fairly pristine shape but yellowed from age. All in all it’s something that I will probably not see again in the near future.



You should re-read John’s post.

Proof cartridges have nothing to do with Calibration components. Proof cartridges use a special case and are loaded to a higher chamber pressure, usually 35% higher, by using heavier bullets, a faster powder, a heavier powder charge, or possibly a combination of the three. They are identified by color markings, a special headstamp, and/or a tinned case.

As John said, the value is in the box and it’s label. I assume that the boxes have been opened which would affect their value downward. 66 per box seems like an odd number so some may have been removed. Are they M2 AP bullets as the label indicates? There are a lot of factors to consider in determining their value.


GAR sent me a photo of his box of Calibration Components and it is unique enough that I asked his permission to post it here.

Plain box, with a closing flap, not made to be sealed. 6 rows of 11 bullets for a total of 66. Very unusual. Maybe a box from something else that FA used for the bullets?

I think he made a good deal.


I can add nothing to this thread except a picture of a sealed 5 round box of .60 cal cases. I believe the headstamp to be * F A * 53 . The primer is electric.

And this one…Headstamp is F A 45 and it is percussion primed.

Just to fill out this thread since we are on the subject, these are some boxes for Calibration Components or Reference Ball Ammunition. “Reference Ball” is a calibration cartridge, either for insuring in testing weapons that the ammunition is not to blame for any malfunctions, or to calibrate test gauges for velocity and pressure.

Top Left: Frankford Arsenal .45 Primed Cases, Steel, Copper prime cups, F A 49

Top Right: Frankford Arsenal .45 Primed Cases, Steel, Copper primer cups, F A 51

Center Left: Olin Corporation Reference Ball, brass case, GM FMJ RN
bullet, brass primer, W C C 7 0. Out of the box, these totally lose
their identity, looking exactly like ordinary ball. We have not even
taken on out to put in our own collection.

Center Right: Blount Inc. (CCI - now part of ATK) 9 x 18m/m Makarov
SAAMI Reference Ammunition, aluminum case, Nickel-cup Berdan primer, GM
FMJ RN, N CCI R 9x18 MAKAROV. Again, out of the box, no identity.

Bottom Center: SAAMI Reference Ammunition .25 Auto - no cartridge
specimen. I am sure it had no special markings on the cartridges.

Collection of John L. Moss

Really neat stuff. Never heard of it before. Hope I didn’t shoot any of it up in the past. But you know me.


I wonder if the odd number of “66” is what just happened to fit in the boxes they had on hand? Maybe someone ordered the wrong sized box or they had a bunch left over from some other project… waste not want not…